Traveling wave electron discharge device



Oct. 31, 1961 c. E. ANDERSON TRAVELING WAVE ELECTRON DISCHARGE DEVICE Filed May 3, 1957 Inventor (WA/255 5 14/ /0545 01V Agent United States Patent Ofifice 3,007,076 Patented Oct. 31, 1961 E- p i k 3,007,076 TRAVELING WAVE ELECTRON DISCHARGE DEVIQE This invention relates to traveling wave electron discharge devices and more particularly to the traveling wave amplifier type.

Traveling wave tubes have various structural configurations. One general form has an electron gun in an enlarged glass enclosure with the radio frequency interaction section and the electron collector electrode disposed in a long, slender glass enclosure. The enlarged enclosure and the long, slender enclosure are integral and provide a glass vacuum housing. The radio frequency interaction section or propagating structure includes an input connection for radio frequency energy at or immediately adjacent the end of the propagating structure adjacent the electron gun and an output connection for radio frequency energy at or immediately adjacent the end of the propagating structure adjacent the collector electrode. These radio frequency connections are usually disposed at right angles to the axis of the interaction section and extend straight outwardly therefrom. This type of tube structure is fragile, and the disposition of the radio frequency energy connections interrupt the effectiveness of the magnetic field and usually necessitates a special type of magnetic structure for the means to produce the magnetic field for electron beam collimation whether it be a solenoid or a permanent magnet.

To overcome the fragility of the glass-envelope traveling wave tube, another general type of tube configuration was derived which employs an all-metal vacuum housing. The usual all-metal tube configuration has an increased housing diameter with respect to the glass tube diameter, particularly in the housing portion enclosing the propagating structure. This increase in housing diameter necessitates employing a larger solenoid than would be employed with a tube having the usual glass envelope, the larger the solenoid, the heavier the weight thereof. Thus, rigidity has been paid for in weight of the solenoid-tube package and increased diameter of the housing particularly in the interaction region. This increased weight becomes an important factor in certain applications, such as in airborne equipment.

Where the housing is kept down in size, whether glass or metal, and both radio frequency connections are brought out at right angles to the axis at the ends of the propagating structure beyond the diameter of the solenoid, as is the usual practice, the solenoid becomes a permanent part of the package. There is no possibility of interchanging tubes and solenoids without dismantling the tube. Thus, the traveling wave tube-solenoid package is further complicated and may necessitate scrapping the relatively expensive solenoid along with a defective tube.

It has been shown that best tube operation results when the following requirements are met. First, the wave propagating structure, such as a helix, should start at a given point along the tube axis where the electron beam is of minimum diameter which is relatively close to the entrance of the electron beam into the interaction region housing. This first requirement is easily met by proper positioning of the end of the helix at said given point. The second requirement is that the solenoid be positioned relative to said given point so that the magnetic field will be at least 90 percent of its total field strength at said given point. This second requirement is very difficult to meet when the radio frequency connections are brought out of the tube at the ends of the helix perpendicular to the tube axis.

Many configurations of glass and metal tubes have been proposed to enable the meeting of the second of the two requirements. The radio frequency connections have been brought out at right angles to the tube axis and then bent to be parallel to the tube axis and disposed within the solenoid inner diameter. In some arrangements the input and output connections have been brought out to one end of the tube by running the input end through the housing or outside the housing, and others have brought them out at their respective ends of the housings. In either case, the solenoid has been properly placed over the input and output connections and the tube itself to satisfy the second of the two requirements and thereby provide the best possible operating conditions. However, it is obvious that this structural arrangement further increases the size of the solenoid needed and hence the weight of the tube-solenoid package. This is without considering the increase in the weight of the tube itself.

An object of this invention is to provide a traveling wave tube structure having a metallic vacuum housing with a diameter in the propagating structure region which is comparable to the diameter of the glass-envelope traveling tube in this region.

Another object of this invention is to provide an allmetal traveling wave tube structure which will reduce the traveling wave tube-solenoid package weight.

Still another object of this invention is to provide a traveling wave tube structure which employs radio frequency terminal connections adjacent each end of the propagating structure disposed in such a manner that there is no interference between the location of the solenoid and the radio frequency terminal connections and which will enable the meeting of the requirements set forth hereinabove for the best possible operation of the traveling wave tube.

A further object of this invention is to provide a traveling wave tube structure with a reduced number of parts and of simple construction.

Still a further object of this invention is to provide a traveling wave tube structure which permits the interchange of traveling wave tubes with solenoids.

A feature of this invention is the provision of a traveling wave tube comprising a vacuum housing including a metallic enlarged portion containing an electron gun for projection of an electron beam along a given rectilinear path and a slender, elongated metallic enclosure for the propagating structure disposed coaxially of said beam path. A first pole piece is disposed transversely of the enlarged housing portion adjacent one end of the long, slender portion. A second magnetic pole piece is disposed at the other end of said long, slender housing portion, said first and second magnetic pole pieces having a portion thereof engaging the inner surface of a magnetic field producing means whether a solenoid or a permanent magnet. Radio frequency input and output means are provided for the propagating structure disposed relative to the ends of said magnetic field producing means to enable the achievement of a substantially maximum magnetic field at the extremities of said propagating structure and the starting of the propagating structure at substantially the point of minimum diameter of the electron beam.

Another feature of this invention is the provision of radio frequency connections at opposite ends of a radio frequency propagating structure, such as a helix, em bedded in the magnetic pole pieces and utilizing the magnetic pole pieces as a portion of a waveguiding structure such as the outer conductor of a coaxial transmission line section.

Still another feature of this invention is the disposition of the output radio frequency connection including as a portion thereof the magnetic pole piece to enable the tube to be slipped into seating arrangement with a magnetic field pro ducing means.

A further feature of this invention is the utilization of an aperture in the magnetic pole piece disposed at the further end of the long, slender housing portion to function as the collector electrode for the electron beam.

Still a further feature of this invention is the utilization of a first coaxial. transmission line section parallel to the beam path and a second coaxial transmission line section at right angles to said first transmission line section embedded in the magnetic pole piece, said magnetic pole pieces functioning as the outer conductor of the coaxial transmission line section to couple radio frequency energy to the propagating structure and yet not interfere with the positioning of the magnetic field producing means.

Still another feature of this invention is the utilization of the magnetic pole piece adjacent the electron gun end of the housing to support the enlarged housing portion and the long, slender housing portion in connected relationship and further to provide a support for the electron gun.

The above-mentioned and other features and objects of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a cross-sectional view of a preferred embodiment of a traveling wave tube following the principles of this invention;

FIG. 2 is a cross-sectional view taken along lines 22 of FIG. 1;

FIG. 3 is a cross-section taken along lines 3-3 of FIG. 1

FIG. 4 is a cross-sectional view taken along lines 44 of FIG. 1; and

FIG. 5 is a cross-sectional view taken along lines 55 of FIG. 1.

Referring to the figures of the drawing, an embodiment of a traveling wave tube incorporating the features of this invention is shown as comprising a metallic housing 1 including an enlarged portion 2 and an elongated, slender tubular portion 3. An electron gun unit 4 is shown to besupported in the enlarged portion 2 for projection of an electron beam along a path within the elongated portion 3. A typical arrangement for such a traveling wave tube is shown as comprising the projection of an electron beam axially along the portion 3 to be in interacting relation with radio frequency propagating structure 5, shown for purposes of examples as including a helical conductor 6 supported by a plurality of ceramic rods 7 to be in interacting relation with the electron beam passing axially thereof.

Electron gun unit 4 forms a pencil-like electron beam which is focussed to have its minimum diameter at substantially the start of the helical structure 6 to thereby meet the first requirement for the best operation of the traveling wave tube. In conjunction therewith, the magnetic field producing means 8 is positioned with respect to the beginning of helical propagating structure 6- such that the magnetic field strength is approximately 90 percent of its full strength at the start of the helical propagating structure 6 thereby meeting the second requirement for the best operation of the traveling wave tube. It is to be understood that the magnetic field producing means may be a solenoid of the well-known type, or it may be a permanent magnet providing suflicient magnetic strength to maintain the electron beam focussed for travel within the helical propagating structure without appreciable interception thereby.

To facilitate the positioning of the solenoid 8 with respect to the beginning of the helix 6, a magnetic barrier member 9 is positioned crosswise portion 2 having its central aperture 10 disposed coaxially of the electron beam path. The input radio frequency connection to helix 6 is provided by means of an aperture 11 parallel to the path of the electron beam and an aperture 12 at right angles to aperture 11 all within the magnetic barrier 9. These apertures 11 and 12 form a waveguiding structure which, in the embodiment illustrated, is coaxial in nature. This is accomplished by disposing spacer 13 of the dielectric material, such as mica, and within aperture 12 spacer 14 of dielectric material, such as mica, to provide positioning and support means for the central conductor 15 which is an extension of the tab 16 of helical conductor 6. This construction is such that we provide a coaxial transmission line section for coupling between the input end of helix 6 to a radio frequency terminal connection 17 of coaxial configuration. The walls of the aperture through a magnetic barrier of pole piece 9 act as a continuation of the outer conductor 18 of the terminal 17, while conductor 15 acts as a continuation of the inner conductor 19 of the terminal connection 17. The relatively small diameter coaxial transmission line section provided in the pole piece 9 in conjunction with the tapered transition section 20 cooperate in matching the high impedance helical transmission line to the relatively low impedance coaxial transmission line and thereby prevents unwanted refiections upon the transfer of energy from the coaxial transmission line 21 to the relatively high impedance helical propagating structure 6.

At the other end of elongated portion 3 removed from electron gun 4 is disposed a second magnetic pole piece 22 which in effect plugs the end of portion 3 and is hermetically sealed thereto. To facilitate coupling to the output end of helical conductor 6, there is provided a waveguiding structure in the form of a coaxial transmission line section 23 including an aperture 24 through pole piece 22 and an inner conductor 25 supported and spaced by the dielectric spacers 26 and 27. The wall of aperture 24 is a continuation of the outer conductor 28 of the output terminal connection 29 of coaxial configuration. The output conductor 28 is secured to the magnetic pole piece 22 by insertion thereof within a counterbore 30 in the end of magnetic pole piece 22 in substantially axial alignment with the electron beam path. Conductor 25 is a continuation of the inner conductor 31 of coaxial terminal 29 for connection to the output end of helix 6. As in case of the input radio frequency coupling means, there is provided a tapered section 32 to cooperate with the reduced diameter coaxial line 23 to provide the necessary impedance transition between the relatively high impedance structure 6 and the relatively low impedance coaxial transmission line. The coaxial arrangement of coaxial terminal 29 is to enable the engaging of the magnetic pole pieces 9 and 22 with the inner surface of magnetic field producing means 8 at 33 and 34, respectively. It is to be understood that this terminal 29 may be at any desired angle to the axis of portion 3 provided magnetic field producing means 8 may be slidably engaged with the portions of pole pieces 9 and 22. The magnetic pole pieces 9 and 22 provide a magnetic field path for the field of the magnetic field producing means 8 and thereby cooperate in concentrating the magnetic field on the axis of portion 33 and hence along the electron beam path within the helical propagating structure 6. This cooperates in providing a more efiioient electron beam collimation arrangement.

The electron beam projected from gun unit 4 is directed toward the magnetic barrier member 22 which includes therein aperture 35 which functions as the collector electrode for the traveling wave electron discharge device. The angular arrangement of anode 38 enables a distribution of the electron beam along a greater area and thereby reduces the heating effect of the electron beam and enables easier cooling of the collector electrode for the traveling wave electron discharge device.

The propagating structure is supported and positioned in its coaxial relation to the axis of portion 3 by means of counterbores 36 and 37 respectively located axially in magnetic barrier members 9 and 22. Magnetic barrier member 9 is further configured to cooperate with the housing portion 2 and the housing portion 3 to provide a connecting support therefor and thus simplifies the manufacture of the traveling electron discharge device. Housing portion 2 is spun over and placed in engagement with magnetic barrier 9 which is then welded or otherwise secured to the spunover portion of housing 2 at 38a. Magnetic barrier 9 further includes a lip 38 having a decreased outer diameter portion 39 for engagement with the tubular portion 3 which is then secured by brazing or other techniques thereto at 39a to provide the completed housing 1.

In a reduction to practice in the traveling wave electron discharge device incorporating the features of this invention, the input coaxial arrangement was provided by one of several ways. This was accomplished by diilling apertures 11 and 12 at right angles to one another for the location of the outer conductor of the coaxial line section. Then, a slot 41 was milled in magnetic barrier 9 to the proper depth above the aperture that is perpendicular to the helical axis, that is, above aperture 12, so that only one half the circumference of the outer conductor of the coaxial line section remained. The inner conductor 15 was then welded to helix tab 16 and the mica or other insulating washers 13 and 14 were positioned to support conductor 15, as shown. The coaxial cover 40 is then placed in the milled slot 41 to complete the circumference of the outer conductor of the coaxial transmission line section. The cover 40 is then trapped in place by a mica sheet 42 and the anode 44 placed in depression 43 of magnetic barrier member 9. The electron gun unit 4 supported as a unit by ceramic rods 45 held in ring 46 is then placed against the mica sheet 42 and anode 44 and then secured to magnetic pole piece 9 by means of bolts 4-7 or other such securing devices. Thus, the magnetic pole piece 9 provides a magnetic path for magnetic field producing means 8, input coaxial transmission lines sections to prevent spaced interference with magnetic field producing means 8, a support and connection between housing members 2 and 3 and a support of the electron gun unit 4.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

I claim:

1. A traveling wave electron discharge device comprising a metallic vacuum housing having a large portion and a slender, elongated tubular portion, an electron gun unit disposed in said large portion to project an electron beam along a path axially of said elongated portion, a helical propagating structure disposed in said elongated portion for propagation of a wave in interacting relation with the electrons of said beam, a first magnetic pole piece having a first aperture therethrough coaxially of said beam path disposed transverse of said large portion adjacent one end of said elongated portion, a second magnetic pole piece disposed crosswise the other end of said elongated portion in hermetically sealing relation therewith, a continuous magnetic field producing means slidably engaging a portion of each of said pole pieces for positioning said magnetic field producing means closely adjacent the outer surface of said elongated portion and abutting said large portion, a radio frequency input means for said propagating structure including a first coaxial terminal extending at right angles to said large portion from said first pole piece and a coaxial transmission line section including a second aperture in said first magnetic pole piece parallel to said beam path, a third aperture in said first magnetic pole piece at right angles to said second aperture and continuous therewith, the walls of said second and third aperture forming a continuation of the outer conductor of said first terminal, and a conductor extending from the input end of said propagating structure coaxially of said second and third apertures forming a continuation of the center conductor of said first terminal, a radio frequency output means for said propagating structure including a second coaxial terminal extending axially of said slender portion from said second magnetic pole piece and a coaxial transmission line section including a fourth aperture in said second magnetic pole piece extending angularly therethrough from a point removed from the axis of said slender Portion to said second terminal, the wall of said fourth aperture forming a continuation of the outer conductor of said second terminal, and a conductor extending from the output end of said propagating structure axially of said fourth aperture forming a continuation of the center conductor of said second terminal and a collector electrode including a fifth aperture in said second pole piece disposed relative to said beam path to collect the electrons of said beam.

2. A traveling wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing with its longitudinal axis parallel to andadjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive with said propagating structure, a first radio frequency wave energy coupling means coupled to the end of said propagating structure adjacent said other end of said housing, said first radio frequency wave energy coupling means including a terminal connection disposed coaxially of said path, and a second radio fre quency wave energy coupling means coupled to the end of said propagating structure adjacent said gun unit, said second radio frequency wave energy coupling means extending from the inside to the outside of said housing adjacent said gun unit in an antiparallel relationship to said path and in a longitudinally spaced, non-interfering relationship with said magnetic field producing means.

3. A traveling wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive with said propagating structure, a first radio frequency wave energy coupling means coupled to the end of said propagating structure adjacent said other end of said housing, and a second radio frequency wave energy coupling means disposed adjacent said gun unit including a first waveguiding portion disposed to extend from the inside to the outside of said housing in an anti parallel relationship to said path and in a longitudinally spaced, non-interfering relation with said magnetic field producing means and a second waveguiding portion continuous with and angularly related to said first waveguidace /gore ing portion in energy coupling relation With the end of said propagating structure adjacent said gun unit.

4. A traveling wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive with said propagating structure, a magnetic pole piece disposed transversely of said housing adjacent each of the ends of said magnetic field producing means to provide a magnetic field path, a first radio frequency Wave energy coupling means coupled to the end of said propagating structure adjacent said other end of said housing, and a second radio frequency wave energy coupling means disposed adjacent said gun unit including a first waveguiding portion disposed to extend from the inside to the outside of said housing in an antiparallel relationship to said path and in a longitudinally spaced, non-interfering relation with said magnetic field producing means and a second waveguiding portion continuous with and angularly related to said first waveguiding portion in energy coupling relation with the end of said propagating structure adjacent said gun unit, said magnetic pole piece adjacent said end of said propagating structure adjacent said gun unit forming a portion of said first and second waveguiding portion.

5. A traveling Wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive with said propagating structure, a magnetic pole piece disposed transversely of said housing adjacent each of the ends of said magnetic field producing means to provide a magnetic field path, a first radio frequency Wave energy coupling means disposed adjacent said gun unit coupled to the end of said propagating structure adjacent said gun unit, and a second radio frequency wave energy coupling means disposed adjacent said other end of said housing including a waveguiding portion in energy coupling relation with the end of said propagating structure adjacent-said other end of said housing disposed in a non-interfering spaced relation with said magnetic field producing means and at an oblique angle with respect to said path, said magnetic pole piece adjacent said end of said propagating structure adjacent said other end of said housing forming a portion of said Waveguiding portion.

6. A traveling wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive with said propagating structure, a magnetic pole piece disposed transversely of said housing adjacent each of the ends of said magnetic field producing means to provide a magnetic field path, a first radio frequency wave energy coupling means disposed adjacent said gun unit including a first waveguiding port-ion disposed to extend from the inside to the outside of said housing in an antiparallel relationship to said path and in a longitudinally spaced, non-interfering relation with said magnetic field producing means and a second Waveguiding portion continuous with and angularly related to said first waveguiding portion in energy coupling relation with the end of said propagating structure adjacent said gun unit, said magnetic pole piece adjacent said end of said propagating structure adjacent said gun unit forming a portion of said first and second waveguiding portion, and a second radio frequency Wave energy coupling means disposed adjacent said other end of said housing including a third Waveguiding portion in energy coupling relation with the end of said propagating structure adjacent said other end of said housing disposed in spaced relation with said magnetic field producing means and in antiparallel relation with said path, said magnetic pole piece adjacent said end of said propagating structure adjacent said other end of said housing forming a portion of said third waveguiding portion.

7. A traveling Wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation With the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive with said propagating structure, a first radio frequency wave energy coupling means coupled to the end of said propagating structure adjacent said other end of said housing, and a second radio frequency Wave energy coupling means disposed adjacent said gun unit including a first coaxial transmission line section disposed to extend from the inside to the outside of said housing in an antiparallel relationship to said path and in a longitudinally spaced, non-interfering relation with said magnetic field producing means and a second coaxial transmission line section continuous with and angularly related to said first transmission line section in energy coupling relation with the end of said propagating structure adjacent said gun unit.

8. A traveling wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive with said propagating structure, a magnetic pole piece disposed transversely of said housing adjacent each of the ends of said magnetic field producing means to provide a magnetic field path, a first radio fre quency wave energy coupling means coupled to the end of said propagating structure adjacent said other end of said housing, and a second radio frequency Wave energy coupling means disposed adjacent said gun unit including a first coaxial transmission line section disposed to extend through said housing in an antiparallel relationship to said path and in a longitudinally spaced, noninterfering relation with said magnetic field producing means and a second coaxial transmission line section continuous With and angularly related to said first transmission line section in energy coupling relation With the end of said propagating structure adjacent said gun unit, said magnetic pole piece adjacent said end of said propagating structure adjacent said gun unit forming the outer conductor of said first and second coaxial transmission line sections.

9. A traveling wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing With its longitudinal axis parallel to and adjacent said path for propagation of Wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive With said propagating structure, a magnetic pole piece disposed transversely of said housing adjacent each of the ends of said magnetic field producing means to provide a magnetic field path, a first radio frequency Wave energy coupling means disposed adjacent said gun unit coupled to the end of said propagating structure adjacent said gun unit, and a second radio frequency Wave energy coupling means disposed adjacent said other end of said housing including a coaxial transmission line section in energy coupling relation with the end of said propagating structure adjacent said other end of said housing disposed in a non-interfering spaced relation with said magnetic field producing means and at an oblique angle with respect to said path, said magnetic pole piece adjacent said end of said propagating structure adjacent said other end of said housing forming an outer conductor of said coaxial transmission line section.

10. A traveling Wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end thereof, an elongated radio frequency propagating structure disposed in said housing with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path having a length greater than the length of said propagating structure to provide a magnetic field along said path having substantially maximum field strength at least coextensive With said propagating structure, a magnetic pole piece disposed transversely of said housing adjacent each of the ends of said magnetic field produc ing means to provide a magnetic field path, a first radio frequency energy coupling means disposed adjacent said gun unit including a first coaxial transmission line section disposed to extend through said housing in an antiparallel relationship to said path and in a longitudinally spaced, non-interfering relation with said magnetic field producing means and a second coaxial transmission line section continuous with and angularly related to said first coaxial transmission line section in energy coupling relation with the end of said propagating structure adjacent said gun unit, said magnetic pole piece adjacent said end of said propagating structure adjacent said gun unit forming the outer conductor of said first and second coaxial transmission line sections, and a second radio frequency wave energy coupling means disposed adjacent said other end of said housing including a third coaxial transmission line section in energy coupling relation with the end of said propagating structure adjacent said other end of said housing disposed in spaced relation with said magnetic field producing means and in an antiparallel relation With said path, said magnetic pole piece adjacent said end of said propagating structure adjacent said other end of said housing forming the outer conductor of said third coaxial transmission line.

11. A traveling Wave electron discharge device comprising an elongated metallic vacuum housing having first and second portions, an electron gun unit disposed in said first portion to project an electron beam along a given rectilinear path in said second portion, an elongated radio frequency propagating structure disposed in said second portion with its longitudinal axis parallel to and adjacent said path for propagation of Wave energy in interacting relation with the electrons of said beam, a magnetic field producing means disposed coaxially of said path at least coextensive with said propagating structure to provide a magnetic field along said path, a first radio frequency wave energy coupling means coupled to one end of said propagating structure disposed adjacent said gun unit, a second radio frequency wave energy coupling means coupled to the other end of said propagating structure spaced from said gun unit, a first magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent said gun unit to provide a magnetic path for the magnetic field thereof, said first magnetic pole piece being disposed within said housing in supporting relation to both said first and second housing portions, and a second magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent said other end of said propagating structure to provide a magnetic path for the magnetic field of said magnetic field producing means.

12. A traveling Wave electron discharge device comprising an elongated metallic vacuum housing having first and second portions, an electron gun unit disposed in said first portion to project an electron beam along a given rectilinear path in said second portion, an elongated radio frequency propagating structure disposed in said second portion With its longitudinal axis Parallel to and adjacent said path for propagation of Wave energy in interacting relation With the electrons of said beam, a magnetic field producing means disposed coaxially of said path at least coextensive with said propagating structure to provide a magnetic field along said path, a first radio frequency wave energy coupling means coupled to one end of said propagating structure disposed adjacent said gun unit, a second radio frequency wave energy coupling means coupled to the other end of said propagating structure spaced from said gun unit, a first magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent said gun unit to provide a magnetic path for the magnetic field thereof, and a second magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent said other end of said propagating structure to provide a magnetic path for the field of said magnetic field producing means and in hermetically sealing relation with the end of said second housing portion spaced from said gun unit.

13. A traveling wave electron discharge device comprising an elongated metallic vacuum housing having first and second portions, an electron gun unit disposed in said first portion to project an electron beam along a given rectilinear path in said second portion, an elongated radio frequency propagating structure disposed in said second portion With its longitudinal axis parallel to and adjacent said path for propagation of Wave energy in interacting relation with the electrons of said beam, a magnetic field producing means disposed coaxially of said path at least coextensive with said propagating structure to provide a magnetic field along said path, a first radio frequency Wave energy coupling means coupled to one end of said propagating structure disposed adjacent said gun unit, a second radio frequency Wave energy coupling means coupled to the other end of said propagating struc ture spaced from said gun unit, a first magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent said gun unit to provide a magnetic path for the magnetic field of said magnetic field producing means, and a second magnetic pole piece disposed adjacent the end of said magnetic field producing means in a hermetically sealing relation with the end of said second housin portion removed from said gun unit to provide a magnetic path for the magnetic field of said magnetic field producing means, said second pole piece including an aperture therein disposed relative to said path to dispose the wall of said aperture in electron collecting relation with said beam.

14. A traveling wave electron discharge device comprising an elongated metallic vacuum housing having first and second portions, an electron gun unit disposed in said first portion to project an electron beam along a given rectilinear path in said second portion, an elongated radio frequency propagating structure disposed in said second portion with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a magnetic field producing means disposed coaxially of said path at least coextensive with said propagating structure to provide a magnetic field along said path, a first radio frequency wave energy coupling means coupled to one end of said propagating structure disposed adjacent said gun unit, a second radio frequency wave energy coupling means coupled to the other end of said propagating structure spaced from said gun unit, a first magnetic pole piece disposed adjacent the end of said magnetic field producing mean adjacent said gun unit to provide a magnetic path for the magnetic field of said magnetic field producing means, and a second magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent the end of said second housing portion removed from said gun unit to provide a magnetic path for the magnetic field of said magnetic field producing means, said second pole piece including an aperture therethrough disposed in an antiparallel relationship with respect to said path and said second radio frequency wave energy coupling means includes a coaxial transmission line section including the wall of said aperture as the outer conductor thereof and a conductor disposed axially thereof in coupled relation to said other end of said propagating structure as the inner conductor thereof.

15. A traveling wave electron discharge device comprising an elongated metallic vacuum housing having first and second portions, an electron gun unit disposed in said first portion to project an electron beam along a given rectilinear path in said second portion, an elongated radio frequency propagating structure disposed in said second portion with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beam, a magnetic field producing means disposed coaxially of said path at least co-extensive with said propagating structure to provide a magnetic field along said path, a first radio frequency wave energy coupling means coupled to the end of said propagating structure disposed adjacent said gun unit, a second radio frequency wave energy coupling means coupled to the other end of said propagating structure spaced from said gun unit, a first magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent said gun unit to provide a magnetic path for the magnetic field of said magnetic field producing means, and a second magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent the end of said second housing portion removed from said gun unit to provide a magnetic path for the magnetic field of said magnetic field producing means, said second pole piece including an aperture therethrough disposed in an antiparallel relationship with respect to said path and said second radio frequency wave energy coupling means includes a coaxial terminal connection secured to the side of said second pole piece removed from said other end of said propagating structure in continuous relation with said aperture and a coaxial transmission line section in cluding the wall of said aperture as the outer conductor thereof continuous with the outer conductor of said terminal connection and a conductor disposed axially of said aperture in coupled relation to said other end of said propagating structure as the inner conductor thereof.

16. A device according to claim 15, wherein said coaxial terminal extends from said second pole piece relative to said path to permit said magnetic field producing means to slidably engage portions of said first and second pole pieces.

17. A traveling wave electron discharge device comprising an elongated metallic vacuum housing having first and second portions, an electron gun unit disposed in said first portion to project an electron beam along a given rectilinear path in said second portion, an elongated radio frequency propagating structure disposed in said second portion with its longitudinal axis parallel to and adjacent said path for propagation of wave energy in interacting relation with the electrons of said beams, a magnetic field producing means disposed coaxially of said path at least coextensive with said propagating structure to provide a magnetic field along said path, a first radio frequency wave energy coupling means coupled to the end of said propagating structure disposed adjacent said gun unit, a second radio frequency wave energy coupling means coupled to the other end of said propagating structure spaced from said gun unit, a first magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent said gun unit to provide a magnetic path for the magnetic field of said magnetic field producing means, and a second magnetic pole piece disposed adjacent the end of said magnetic field producing means adjacent the end of said second housing portion removed from said gun unit to provide a magnetic path for the magnetic field of said magnetic field producing means, said second pole piece including a first aperture therein disposed relative to said path to dispose the wall of said first aperture in electron collectin relation with said beam and a second aperture therethrough, and said second radio frequency wave energy coupling means includes a coaxial transmission line section including the wall of said second aperture as the outer conductor thereof and a conductor disposed axially of said second aperture in coupled relation to said other end of said propagating structure as the inner conductor thereof.

18. A traveling wave electron discharge device comprising a metallic vacuum housing having a large tubular portion and a slender, elongated tubular portion, an electron gun unit disposed in said large portion to project an electron beam along a given path in said housing parallel to the longitudinal axis of said housing, an elongated radio frequency propagating structure disposed in said slender portion coaxially of said path for propagation of wave energy in interacting relation with the electrons of said beam, a first magnetic pole piece disposed in said large portion adjacent one end of said slender portion in a transverse relationship to said longitudinal axis, said first magnetic pole piece having an aperture therethrough coaxial of said path, a second magnetic pole piece disposed at the end of said slender portion spaced from said large portion in transverse relation to said longitudinal axis in a hermetically sealing relation with said slender portion, a magnetic field producing means slidably engaging a portion of the outer surface of each of said pole pieces, a first radio frequency wave energy coupling means in energy coupling relation with one end of said propagating structure and a second radio frequency wave energy coupling means in energy coupling relation with the other end of said propagating structure, said first and second radio frequency wave energy coupling means being disposed respectively at opposite ends of said slender portion, and in an antiparallel relationship With respect to said path to enable movement of said slender portion into engagement with said magnetic field producing means;

19. A traveling Wave electron discharge device comprising an electron gun unit for projecting a beam of electrons along a given path, a radio frequency propagating structure disposed coaxially of said path for propagation of Wave energy in interacting relation with the electrons of said beam, a metallic vacuum housing having a first portion enclosing said gun unit having an enlarged configuration and a second portion enclosing said propagating structure having a slender, elongated tubular configuration, a first magnetic pole piece disposed in said first housing poltion adjacent said second housing portion in a transverse relation with said path, a second magnetic pole piece disposed at the end of said second housing portion removed from said first housing portion in a transverse relation with said path, a first radio frequency wave energy coupling means in energy coupling relation with the end of said propagating structure adjacent said first pole piece including as a portion thereof an aperture disposed in said first magnetic pole piece in an antiparallel relationship to said path and a second radio frequency wave energy coupling means in energy coupling relation with the end of said propagating structure adjacent said second pole piece including as a portion thereof an aperture disposed in said second pole piece in an antiparallel relationship to said path.

20. A traveling wave electron discharge device comprising an elongated metallic vacuum housing, an electron gun unit disposed in one end of said housing to project an electron beam along a given rectilinear path in said housing toward the other end of said housing, an elongated radio frequency propagating structure disposed in said housing coaxially of said path for propagation of Wave energy in interacting relation with the electrons of said beam, a continuous magnetic field producing means disposed coaxially of said path to provide a magnetic field along said path coextensive with said propagating structure, a first magnetic pole piece disposed in a transverse relation with said path adjacent the end of said propagating structure adjacent said gun unit, said first pole piece being in contact with the end of said magnetic field producing means adjacent said gun unit to provide a low reluctance magnetic field path, a second magnetic pole piece disposed in a transverse relation with said path in a hermetically sealing relation with said housing adjacent the end of said propagating structure spaced from said gun unit, said second pole piece being in contact with the end of said magnetic field producing means spaced from said gun unit to provide a low reluctance magnetic field path, a first radio frequency Wave energy coupling means in energy coupling relation with the end of said propagating structure adjacent said first pole piece including as a portion thereof an aperture dis posed in said first magnetic pole piece in an antiparallel relationship to said path and a second radio frequency wave energy coupling means in energy coupling relation With the end of said propagating structure adjacent said second pole piece including as a portion thereof an aperture disposed in said second pole piece in an antiparallel relationship to said path.

References Cited in the file of this patent UNITED STATES PATENTS 2,652,513 Hollenberg Sept. 15, 1953 2,788,465 Bryant et al Apr. 9, 1957 2,794,144 White May 28, 1957 2,797,353 Molnar et al. June 25, 1957 2,812,470 Cook et al. Nov. 5, 1957 2,812,473 Mourier Nov. 5, 1957 2,844,750 Veith et al. July 22, 1958 2,844,754 Cioffi July 22, 1958 2,848,645 McBee Aug. 19, 1958 2,871,395 Cioifi Jan. 27, 1959 2,887,608 McBee May 19, 1959 OTHER REFERENCES RCA Magnetrons and Traveling Wave Tubes, Radio Corporation of America, Tube Division, Harrison, N.J., 39 pp. June 1956. 

